Centerless grinder



Jan. 27, 1942. A. SCRIVENER CENTERLESS GRINDER Filed June 9, 1941 NEIARTHUR SCRIVENER N INVENTOR V BY M M TTORNEYS Patented Jan. 27, 1942CENTERLESS GRINDER Anna? serr'v'ener, B's Application June 9",1941-;lSeriaI. No. 391,202 c In Great Britain Aiiril 8, 1940' mnihanfnnglana speedmgmpdn theamotnt-ofwork which can b'eproducedin' agiven time by 'the'machine with a. minimum or a physical start of theoperator; The invention consists of improvements in or 'connected withcenteness grinde'rs; wherein means are" provided for effetting a'power-operated' release of the workpiece upon the co'mple- 'tion or thegrinding o eration; saidpower operation'wbeing effected from a;mechanicaior ele'c-s tri'cali or ether ower drive which -is coupled tothe release mechanism at: and for the p'eritd of 1 the'releas operationzY mediately withinbutfree from contact with the Ve'driving-sur'faceofthepulley! i a length ,or section of. resilient V=belting 5 which issecured to the undersurface of a bar 6 which is'aligned withjl'andlinkediby means of the pin 1 to the springs-loaded hammer bar" 3.Normally this hamme'rbar 3 and consequently the bar 6 which islinketi'thereto. are maintained at their posi tionlof rest as seen inFig I of the drawing,,free 'o'f the' workpiece or of the interposedspringloaded member 8, by means of coiled compressionspri'ngs 9 and 9adisposed around the ham:- mer bar '3'within' a slotted framework 10 inwhich the bar is mounted. within the, bearings 1'06," one end .of each"spring Sand 9a. bearing againsttheframework In and the otherend of "eachspring bearingagai-nst the respective abutment's l'l' and He pinned tothe'hammer bar 3;

, O'ne means of carrying the present invention into efiectas applied toa centerless grinder of 7 known construction will now be described withreference to the accompanying sheet of drawings. in which: a

Fig. 1 is a part sectional side elevation illustrating the releasemechanism.

Fig. 2 is a part sectional fragmentary view illustrating the triggerrelease mechanism which is associated with the mechanism seen in Fig. 1through a flexible control.

The release of the workpiece is effected as in accordance withexisting'practice by imparting to the workpiece upon completion of thegrinding operation and immediately subsequent to or coincident with thefreeing movement of the grinding wheels a blow either directly on oneend or face of the workpiece or on a member interposed between thehammer and the workpiece which ensures its positive release or dischargefrom the grinding position. Ordinarily this blow is imparted by means ofa springloaded hammer bar which is designed to give a blow through apositive link connection which is entirely under the manual control andoperation of the operator, and in the case of heavy work or largermachines might involve a considerable amount of physical energy In thepresent machine a illustrated by the accompanying drawing the hammerblow or release motion of the hammer bar 3 is imparted by a power driveefiected say by means of a continuously running small electric motor onthe spindle of which is mounted a Vpu1ley 4. Located im- Mountedadjacent to the striker'end of the hammerbar 3: and pinned thereto isanother; abutmerit l-z-wliich serve'szto contactthe outer end of thslotted framework I0 'andsconstitutesyan inner l mit' s'top fortheh'ainme'r bar-16.11 1

" 'lhei section orlengthot V-belting J 5 and. the bar 6 to which it issecured are normally maintained in a slightly raised or free positionrelative to the peripheral V of the driving pulley 4 by means of a pairof slidably mounted guide wheels I3, 13a. disposed one aboveand theother below the belt-carrying bar 6, the pair of rollers l3, l3'a beingmounted in a slide block I4 disposed and vertically movable withinone'end of the slotted framework It], the said slide block and guidewheels being capable of initial adjustment or setting within theirmounting in the framework by means of an adjusting screw and nutconnection [5 having a coiled spring l6 introduced between theundersurface of the ,nut and one face of the framework II]. To the lowerend of this slide block Hi there is pivotally connected one end of aflexible cable I! which extends to and is connected at its other endwith a pivotally mounted bracket l8 which constitutes part of a triggermechanism.

The bracket I8 is mounted to pivot about the pin 18a and is providedwith an adjustable stop lBb which determines the limit of pivotal motionof a co-operating trigger part l9 which can be moved through an areabout its pivot I911 on the bracket I8, the limit of motion of thetrigger part I!) relative to the bracket l8 being determined in the onedirection by means of the set ting of the adjustable stop [8b mounted onthe bracket l8. The trigger l9b which forms part of the trigger part l9hereinbefore referred to is contacted by the co-operating trigger 20mounted on the crank 2| which rocks about the spindle 2|a, motion beingimparted to the crank 2| through a link rod 22 pivotally connected tothe arm of the crank. The link rod is. pivotally connected at its otherend to a release lever (not shown) which is operated to release thegrinding wheels and free the workpiece in accordance with knownpractice. The trigger 20 is by this release motion given a motion in thedirection of the arrow (Fig. 2) when it will contact with thecomplementary trigger l9b, rock the part [9 into contact with theadjustable stop I81) and thereby rock the bracket I8 about its pivot 18ato exert a pull on the flexible cable IT. The return of the bracket I8and trigger part 19 is effected tively engage the peripheral V groove ofthe driven pulley associated with the electric motor; thus there isimparted to the bar 6 and to the hammer bar 3 pivotally connectedthereto a sudden longitudinal motion .to the left in the direction ofthe workpiece, against the resistance of the pair of coiled compressionsprings 9 and 9a surrounding the hammer bar 3, thereby causing the freeend of the hammer bar to strike the workpiece or a spring-loaded member8 interposed between the hammer bar and the workpiece and positivelyrelease or discharge the workpiece from its now released position withinthe grinding by the pull of the coil spring I6 "through the slide blockM to which the other end of the flexible cable I! is anchored, the crank2| being returned to its normal position as seen in Fig. 2

of the drawing by the operation of the'irelease lever which is pivotallyconnected to the link rod 22; a'trip action obtaining between thecomplementary-triggers 20 and l9b.

' The operation of the mechanism is as follows: When the grindingoperation has been completed the release lever of the machine is movedthrough an are thereby causing the trigger which is associated therewithto contactiwith. the trigger l9b forming part of the trigger part I9pivotally mounted on the pivotal bracket I8, .to one part of which theflexible cable I! is: anchored as clearly'seen in Fig. 2, whereby alimited arcuate motion is imparted to the bracket I8 aboutv its pivotIsa, thus transmitting a pull to the flexible cable I! whichin turnpulls down the slideiblock l4 together with the pairof rollers l3 l3a1(the lower one of which l3a serves to normally sup- 7 port in theraised position the slide bar 6 through the V section or length ofbelting mounted thereon); againstithe :resistance of the coiledcompression spring l6 which is associated with the slide block 14. Thismotion causes the sectionior lengthof V-belting tomomentarilyposiwheels, the only effort required by the operator to effect thisrelease being that of causing an engagement between the two triggershereinbefore referred to, which is a slight, limited operation, thewhole of the positive energy required for effecting a blow of the hammerbar being obtained from the power drive of the electric motor. V

It will be appreciated that in place of the electric'motor there may besubstituted a continuously rotating pulley driven from any convenientpower source which would be coupled to the V-pulley 4.

I.claim: n

A centerless; grinder comprising, in combination, ahammer unit forejecting the workpiece, biased toward itsinoperative position, afriction surface ,ona portion of the hammer unit, a'constantly rotatingfriction member normally spaced from said friction surface. said portionof the hammer unit and said rotating friction member being movablerelative to one another to bring said friction member and said'frictionsurface into contact; and the direction of rotation of said frictionmember being such that upon establishment of such contactqan ejectingmove;- ment is imparted to. the hammerunit, and actuating means forbringing said rotating friction member and said frictionsurface intocontact.

5 ARTHUR SCRIVENER;

